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求教：一道关于栈的问题

Alen0128 发布于 2010-07-19 09:42， 963 次点击

这是有关于栈的一道ACM题，我做了一下，有问题，貌似是判断栈空是出错了，请教大侠们

（我的代码在最下面）
下面是问题的描述：

Problem Description：
As the new term comes, the Ignatius Train Station is very busy nowadays. A lot of student want to get back to school by train(because the trains in the Ignatius Train Station is the fastest all over the world ^v^). But here comes a problem, there is only one railway where all the trains stop. So all the trains come in from one side and get out from the other side. For this problem, if train A gets into the railway first, and then train B gets into the railway before train A leaves, train A can't leave until train B leaves. The pictures below figure out the problem. Now the problem for you is, there are at most 9 trains in the station, all the trains has an ID(numbered from 1 to n), the trains get into the railway in an order O1, your task is to determine whether the trains can get out in an order O2.

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Input
The input contains several test cases. Each test case consists of an integer, the number of trains, and two strings, the order of the trains come in:O1, and the order of the trains leave:O2. The input is terminated by the end of file. More details in the Sample Input.

Output
The output contains a string "No." if you can't exchange O2 to O1, or you should output a line contains "Yes.", and then output your way in exchanging the order(you should output "in" for a train getting into the railway, and "out" for a train getting out of the railway). Print a line contains "FINISH" after each test case. More details in the Sample Output.

Sample Input
3 123 321
3 123 312

Sample Output
Yes.
in
in
in
out
out
out
FINISH
No.
FINISH

6 回复

#2

Alen01282010-07-19 09:42

程序代码：

#include <stdio.h>
#include <stdlib.h>

typedef struct Node
{
    char order[9];
    int top;
}Train;

void Push(Train* train);
char Pop(Train* train);
int Judge(Train* train, char order[], int icase);
void Print(int icase);
int Empty(Train* train);

int main()
{
    int i = 0;
    int icase = 0;
    Train* train = (Train*)malloc(sizeof(Train));        //order1
    char order[9];                                        //order2

    while (scanf("%d",&icase)!=EOF && icase<10)
    {
        getchar();
        train->top = -1;

        for (i=0; i<icase; i++)
        {
            Push(train);
        }

        getchar();

        for (i=0; i<icase; i++)
        {
            scanf("%c",&order[i]);
        }

        if (Judge(train,order,icase))
        {
            printf("YES.\n");
            Print(icase);
            printf("FINISH\n");
        }
        else
        {
            printf("NO.\n");
            printf("FINISH\n");
        }
    }

    return 0;
}

void Push(Train* train)
{
    train->top++;
    scanf("%c",&train->order[train->top]);
}

char Pop(Train* train)
{
    char result = ' ';

    result = train->order[train->top];
    train->top--;

    return result;
}

int Judge(Train* train, char order[], int icase)
{
    int i = 0;

    for (; i<icase; i++)
    {
        if (Pop(train) == order[i])
        {
            continue;
        }
        else
        {
            return 0;
        }
    }

    if (Empty(train))
    {
        return 1;
    }
    else
    {
        return 0;
    }
}

void Print(int icase)
{
    int i = 0;

    for (; i<icase; i++)
    {
        printf("in\n");
    }

    for (i=0; i<icase; i++)
    {
        printf("out\n");
    }
}

int Empty(Train* train)
{
    if (train->top == -1)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}

#3

2010-07-22 06:47

应该是你的算法有问题，我举个例子123，213，两个序列可以转换，可是用你的算法判断是错的。

#4

2010-07-22 07:49

还有就是下次加点注释。

[ 本帖最后由 LegendofMine 于 2010-7-22 07:54 编辑 ]

#5

Alen01282010-07-30 17:23

回复 3楼 LegendofMine

不好意思，回晚了
这个123,213怎么意思？

#6

hzh5122010-08-09 11:35

ACM经典老题目了，就是给出所有可能的出栈序列

1